Current therapy of Trypanosoma evansi infections is not
effective for the vast majority of animals with relapsing parasitemia and
clinical signs. Recently, attention is being focused on the antiparasitic
activity of propolis.

This study evaluated the susceptibility of T. evansi to
propolis extract in vitro and in vivo.

A dose-dependent trypanocidal activity of propolis extract
was observed in vitro. All trypomastigotes were killed 1 h after incubation
with 10 μg mL−1 of the extract. In vivo, the concentrations of 100, 200, 300
and 400 mg kg−1 administered orally for 10 consecutive days showed no curative
effect, and the rats died from the disease. However, rats treated with the two
highest concentrations of propolis extract showed higher longevity than the
other groups.

Based on these data, we concluded that T. evansi is
susceptible to propolis in vitro. Despite the lack of curative efficacy
observed in vivo at the concentrations tested, the propolis extract can prolong
life in rats infected with the protozoan.